package com.xiaoge.demo.configs.annotation.token;

import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.xiaoge.demo.dao.UserDao;
import com.xiaoge.demo.pojo.User;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import java.lang.reflect.Method;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import lombok.extern.slf4j.Slf4j;

/**
 * 描述：  token拦截器
 * 作者：  郭永振
 * 时间：  2018-9-10 16:49:34
 */
@Slf4j
public class TokenInterceptor implements HandlerInterceptor {
    @Autowired
    UserDao mUserDao;

    @Value("${customer_settings.token.header}")
    private String headerStr; // header中存放token的字段名称
    @Value("${customer_settings.token.httpCode}")
    private int tokenExceptionCode; // token异常返回的httpCode

    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object object) throws Exception {
        String reqURL = httpServletRequest.getRequestURL().toString();
        // log.debug("Token拦截器：" + reqURL);
        String token = httpServletRequest.getHeader(headerStr);// 从 http 请求头中取出 token
        // 如果不是映射到方法直接通过
        if (!(object instanceof HandlerMethod)) {
            return true;
        }
        HandlerMethod handlerMethod = (HandlerMethod) object;
        Method method = handlerMethod.getMethod();
        // 检查是否有passToken注释，有则跳过认证
        if (method.isAnnotationPresent(PassToken.class)) {
            PassToken passToken = method.getAnnotation(PassToken.class);
            if (passToken.required()) {
                return true;
            }
        }
        // 检查有没有需要用户权限的注解
        if (method.isAnnotationPresent(RequestToken.class)) {
            RequestToken requestToken = method.getAnnotation(RequestToken.class);
            if (requestToken.required()) {

                return true;
            }
        }
        // 执行认证
        if (token == null) {
            // throw new TokenException("token不能为空");

            // 直接在httpCode中返回token请求失效
            httpServletResponse.sendError(tokenExceptionCode, "token不能为空");
            return false;
        }
        // 获取 token 中的 user id
        String userId;
        try {
            userId = JWT.decode(token).getAudience().get(0);
        } catch (JWTDecodeException j) {
            // 在code中返回token失效
            // throw new TokenException("无效token");

            // 直接在httpCode中返回token请求失效
            httpServletResponse.sendError(tokenExceptionCode, "token无效");
            return false;
        }
        User user = mUserDao.getOne(userId);
        if (user == null) {
            throw new TokenException("用户不存在，请重新登录");
        }
        try {
            // 验证 token
            JWTVerifier jwtVerifier = JWT
                    .require(Algorithm.HMAC256(String.valueOf(user.getId()))) // 通过令牌解密
                    .build();
            jwtVerifier.verify(token);
        } catch (Exception e) {
            // throw new TokenException("token失效 请重新获取token");

            // 直接在httpCode中返回token请求失效
            httpServletResponse.sendError(tokenExceptionCode, "token失效 请重新获取token");
            return false;
        }
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest,
                           HttpServletResponse httpServletResponse,
                           Object o, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest,
                                HttpServletResponse httpServletResponse,
                                Object o, Exception e) throws Exception {
    }
}